HTML subheadings used to organize supporting topics into a meaningful hierarchy.
H2 through H6 are HTML heading levels used to organize sections and subsections. In a common page structure, H2 marks a main section beneath the page heading and H3 marks a subsection within it. The level describes the relationship between sections, not how large the text should look.
A useful heading outline lets someone understand the page before reading every paragraph. It also supports navigation for people using assistive technology. Descriptive section names are more helpful than repeated labels such as “More Information” when the sections cover different subjects.
Choose levels by hierarchy rather than by the default font size in an editor. Avoid skipping downward from a major section to a much deeper level merely to get a smaller heading style. Returning to a higher-level heading to start the next major section is different: that closes the previous subsection and continues the outline.
Takeaway: Organize the page around questions and decisions readers actually need to navigate. Clear sections make a long explanation easier to use without forcing every page into the same template.
Example
An equipment-hire page could use H2 sections for “Choosing Equipment,” “Delivery” and “Returns.” Within Delivery, H3 headings might cover access requirements and appointment preparation. The Returns section then returns to H2. This structure reflects the subjects’ relationships rather than presenting every heading as an equally important topic.
What to check
Read the headings alone as a quick outline test. If they form a confusing sequence, revise the structure or labels before adding more copy. Use CSS to change appearance rather than choosing an incorrect heading level for its size.
For more detail, see Headings: W3C Web Accessibility Initiative.